Skateboard shelf



FIG. 1 is a front perspective view of a skateboard shelf in accordance with my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines shown are included for the purpose of illustration and form no part of the claimed design. 

The ornamental design for a skateboard shelf, as shown and described. 